as you mentioned your mother symptoms like fever and chills and anorexia with R/E showing 20-30 pus cells more indicating towards UTI .she should go for more investigations like urine culture & sensitivity, complete blood count
& blood culture
and blood glucose estimation(fasting and pp).
Ensure proper hydration, give her full bed rest, antipyretic
500mg 3-4 times a day, tab ofloxacin 200mg bd for 1-3 days/cephalexin 250mg 6 hourly for 1-3 days and also maintain proper hygiene. consult a physician for further evaluation. hope this will help you.